The present invention relates to a bone pin which is used to secure small bone fragments together and which is made from a polymeric material, preferably a polymer which is absorbable in an animal body. The bone pin of the present invention has a cutting or drilling device secured to one end of the polymeric portion of the pin so that the pin may be directly inserted into a bone or a bone fragment.
Bone pins are generally made from a medical grade metal which can be placed in an animal body for extended periods of time without adverse effect. The metal bone pins are normally removed from the body after the bone has healed. The metal bone pins, particularly a bone pining device called a Kirschner wire, may have a sharpened end which can be used as a drill point to drill the pin through the bone.
The use of plastic such as polyethylene as a bone pin has been suggested. Bone pins made from polymeric materials which are absorbable in the body has also been suggested. These bone pins can be made from polyglycolide or polylactide polymers or copolymers or glycolide and lactide or from poly-dioxanone or other absorbable polymers. A bone pin made from poly-dioxanone as disclosed in U.S. Pat. No. 4,052,988 has been commercially available for some time.
The poly-dioxanone bone pin is employed by drilling a hole through a bone fragment and into a solid bone or between or through two adjacent fragments of bone which are to be held together. After a hole of the proper diameter is drilled through the bone, the drill is removed and the poly-dioxanone pin is inserted through the hole and the portion of the pin extending beyond the bone surface is removed by cutting with a scalpel or other instrument.
The problem with this procedure is that when the initial hole is drilled through the bone the bone fragments are aligned, after the drill is removed in order to insert the pin, the fragments may become misaligned which causes difficulty in properly inserting the pin.